class Student:
    def __init__(self,name):
        name='Unkown'
        self.name=name

stu1=Student('Unkown')
stu2=Student('Unkown')
print("Student.name:Unknown")
print(f"stu1.name{stu1.name},stu2.name:{stu2.name}")
stu1.name='李明'
print(f"Student.name: 未知 stu1.name:{stu1.name},stu2.name: 未知")